See through PR

[bwg]

This is my first foray into casting PR blanks. As you can see in the photo, the cast is not totally opaque. However when it was still liquid and before it was polished, it appeared to be totally opaque. This happens, to a certain extent with acrylic blanks that I buy.
Does anyone know the reason for this? Am I doing something wrong?
All I did was polish with a series of micro mesh (up to 4000) pads and then polished with rouge on a paint roller.
How does one know when it is actually opaque when mixing?

Thanks
Bruce

 

[robertkulp]

You should paint the tubes and/or the inside of the blank after drilling for all "acrylic" blanks.

When you're looking through a 3/4" blank, it will probably look opaque, but when you turn it down to size, you're only looking through .08" - .15". It's really easy for the tube to "show through" that little bit of resin.

 

[mecompco]

Did you paint your tubes before casting? I always paint mine. I've also learned to seal them with clear Mod Podge spray so the PR doesn't dissolve paint.

When using pre-made blanks, paint the tube, paint the inside of the drilled blank, and if you're paranoid (like me), also color your epoxy. Oh, and not a bad idea to sand the inside of a drilled blank before painting to eliminate any stray drill marks.